Anyone listen to Zu Audio's Definition Mk3?

Glory,

I live in an area with fairly dirty power. I've investigated a lot of power conditioning and of course, all choices sound different and none so far have been completely positive in their effects. But I haven't by any means auditioned a comprehensive list of candidate conditioners. Currently my sources and preamplification are fed by balanced power/isolation transformers, and my power amps get lightly filtered inductorless AC conditioning. Sometimes I plug the power amps directly into the wall just to remind myself of the difference. I am considering BPT or Furman full balanced power isolation for both whole systems, including amperage capacity for power amps, this year.

My gear in both systems rests on custom made solid maple tables, each identical at 6' long, 23" deep, with total height of 17-3/4". The top surface of these tables is an expanse of lamintated 1-1/2" thick solid maple boards, for 3" total tabletop thickness. The second shelf under neath is solid 1-1/2" thick solid maple boards. The legs are 2-1/2" x 2-1/2" solid maple. The bottom of each leg has a 2" diameter x 2" tall height-adjustable brass cone. The cone points rest on Herbie's Cone Decoupling Gliders (brass receptor/stiff elastomer/teflo). My turntables sit on the top 3" layer, on Aurios Media Bearings. My phono & line preamps, and SUTs also sit on this layer, on Herbie's Grungbuster Dots. My optical disc players sit on the lower 1-1/2" thick shelf on Aurios Media Bearings. I live in a slab house, so this being California, the turntables are great for listening to the planet if I remove the Aurios. Better for music with the Aurios in place. But also, being a slab house, footing is very firm for everything.

Zu crossoverless design: The simple answer is there's no splitter between the power amp outputs and the main driver(s). The more complete answer: There are variances in internal wiring from model to model in Zu's line, but the essentials are all shared. Every Zu speaker is architected around their 10" FRD (Full Range Driver), which some sticklers will insist should be referred to as a "wideband driver" or "widebander." In each Zu speaker, the widebander is handles the frequency range of about 38Hz - 12kHz. In the simple 2-driver speakers, the power amp will "see" the widebander's voice coil directly. In Definition, Omen Def, Dominance, there's a little more going on schematically. But nevertheless, unlike a conventional multi-driver louspeaker incorporating a passive crossover, the amplifier signal is NOT passed through a passive crossover that splits signal before the widebander gets signal. So the power-eating inefficiencies and phase non-linearities, not to mention the tonal colorations and distortions of conventional passive crossovers are not introduced. Instead, a supertweeter is included for top end sparkle and harmonic completeness, and it is rolled in by a gentle passive high-pass filter roughly inverse to the natural acoustic roll-off of the top end response of the widebander. No circuitry enforces the roll-off of the widebander. In Definition and Dominance, which include extended bass performance through built-in powered sub-woofers, input to the sub-amp comes from a fixed low-pass filter that in Def 1 & 2 approxomated its roll-in to complement the natural acoustic roll-off of the widebander's low end response, with an amp level control added. In Def4 and Dominance, this low pass filter is now active and adjustable within specific ranges, for more precise matching of bass performance to a wider range of rooms and placement conditions. The key point is that the main driver -- the FRD or the widebander -- that outputs 90% of the music content that defines your listening experience, is receiving an unfiltered signal that's undisturbed by an intervening crossover. High and low pass filters for frequency extension simply complement the natural roll-offs of the widebander's response.

Phil

A bottom line question -

After reading many statements about Zu, Tekton, and other cross overless speaker brands and unsuccessfully bidding on a pair of Essences can I simply put a system together without worrying about all of the detailed issues being discussed?

Can I place Omen Defs in a medium sized (open) family room with a modest 85 watt receiver (or find a used integrated amp like Melody which the Zu people mentioned would work) and a Marantz cd player together and not have to worry about what I am missing? Would I get better sound than from a 1992 pair of Emit Infinitys?

Phil, I really value your thoughts/opinions on all these topics, I think I'm getting a handle on all the decisive factors in going to the next level. The UK Audion dealer demos the Audion SETs thru the Audion Premier valve line stage pre amp, are you familiar with this unit? I see that you personally run your Black Shadow 845s thru a Klimo pre amp, any reasons why no Audion pre? If I go down the SET route, I may keep the Hovland HP200 pre to run things thru, and relegate the Hovland Radia to AV rear channel duties (a bit of a shame since I really love it's sound), unless the Audion Premier or Silvercore/Music First TVCs do it for me. The UK dealer really rates the Silvercore: it's a fantastically put together piece of kit, maybe it could swing you back to the TVC fold if you heard it?
I'm a little suprised to see that even though you run a balanced power transformer in your system, which I do and heartily recommend, you still apply conditioning to the power amp. For years I ran everything thru a Burmester 948 conditioner ($6000+), and despite all the transparency improvements wrought over untreated mains, there was definitely a squeezing of dynamics. Switching to a cheap ($600) 4kV industrial balanced power transformer, all the transparency was maintained with a fantastic increase in dynamic grip; I'll NEVER go back to any conditioning again, and am v. interested in looking at a pro transformer Westwick, 85kg! of copper 8kV isolation. So, you still feel even with balanced isolation to mains you still need conditioning to the power amp?

Obrown,

I am certainly no expert like Phil, but I have 2 pairs of Omen Defs (one with upgrade HO drivers, caps and internal wiring, and one stock pair). I have them in an upstairs loft, 35' x 15' x 8' (the second pair used for surround sound right now). I have taken the non-upgraded pair down into our family room and hooked them up to a 65 watt Yamaha receiver. That room is about 25' x 20' x 9' and opens into a very large kitchen area. The Omens sound very, very good even in the family room with the Yamaha receiver. I find the Zu speakers to be very good in almost any setup (especially the Omen Defs, which are very friendly to solid state equipment) -- I don't think you will have a problem with just plopping them down and getting good sound (much better than a 1992 pair of Infinity speakers -- I used to own the RS3B's).

That being said, I have found that with a little work and persistence, the Omen Defs can sound fabulous. It takes some time fiddling with the gap space under the speaker to the amount of distance between the speakers and toe-in to get the best results, but mine have never sounded bad in any room, in any set-up. I have found they tend to sound better to me with a wider distance between the speakers and more toe-in, compared to other speakers I have owned.

I do use an Audion Premier preamp on one of my systems. It is an earlier generation, with full remote control (volume plus switching). The sound of Audion preamps is in the same class as their power amps. The Klimo is in one system as a consequence of once having had Audiopax 88 power amplifiers, for which Audion's preamps did not have enough gain to drive (the Audiopax having only 18 db of gain and unusually low input sensitivity, requiring a preamp of 20 - 25 db gain), and the Klimo brings similar qualities so there was no need to replace it when I replaced the Audiopax with Audion's Black Shadow.

My Black Shadow monoblocks don't consume enough power to be dynamically constrained by light power conditioning. When I had higher-power amplifiers in the past, I did run them straight from the wall but in this case there's no dynamic difference. It's a peculiarity of my present location that mild power conditioning lowers the noise floor a bit whithout dynamic penalty. In another power neighborhood my configuration might be different. I'll likely add balanced power for the power amps and when I do, I am sure I won't be using power conditioning with it.

But I'll make an earlier point again: Balance is my measure, and that includes balance between my interests. My systems are in a good state of equilibrium today. My next push is to prepare for adding hard disk playback by settling on DAC choices that also benefit optical disc playback.

Phil